Pc3-4 pulsations are an ubiquitous element of dayside ULF wave activity both at low-latitude and in the cusp region. We compare simultaneous observations of Pc3-4 wave activity by magnetometers at three locations on Svalbard, covering geomagnetic latitudes 74o-76o, and by low-latitude SEGMA magnetometer array (36o-43o). The cross-spectrum between low-latitude stations shows a typical amplitude-phase gradient pattern – maximal phase delay at specific resonance frequency, which confirms that the ground response is formed due to the conversion of external band-limited disturbances into standing field line oscillations. At the same time, the gradient analysis shows no specific mode conversion pattern near the cusp region. The amplitude gradient has the same direction at all frequencies, and the phase delay does not show any consistent pattern. This behavior corresponds to the occurrence of a localized peak in the latitudinal distribution of Pc3-4 power not under the cusp proper, as was previously thought, but about few degrees southward from the equatorward cusp boundary.

This paper was published as : Physics of Auroral Phenomena, Proceedings of XXXII Annual Seminar, Apatity, 3-6 March, 2009, pp. 89-92. It is available from http://www.kolasc.net.ru/ksc/main/mdir1.htmlMetadata only entry